Greatest possible error

  • The Greatest Possible Error (GPE) is the maximum amount by which a measured value could differ from the true value due to limitations of the measuring instrument.
  • It represents the uncertainty of a measurement.
  • The GPE is half of the smallest measurement unit of the instrument used.
  • Formula:

Greatest Possible Error = Smallest Division of the Instrument / 2

  • Example: If a ruler measures in millimeters (mm), the GPE is 1/2 mm = 0.5 mm.
  • Helps understand the accuracy and precision of measurements.
  • Essential in fields like science, engineering, and construction, where exact measurements are crucial.
  • Absolute Error: The GPE expressed in measurement units (e.g., ±0.5 cm).
  • Relative Error: The GPE divided by the measured value, often expressed as a percentage.

If you measure a table’s length as 100 cm using a ruler with 1 cm divisions:

GPE = 1 cm / 2 = 0.5 cm

The actual length could be between 99.5 cm and 100.5 cm.

  • In construction, small errors can lead to significant structural problems.
  • In scientific experiments, GPE helps determine the confidence level of results.
  • Precision: How detailed a measurement is.
  • Accuracy: How close a measurement is to the true value.
  • Uncertainty: The range in which the true value is expected to lie.

Learn with an example

  • The measurement of 8 metric tons was made to the nearest whole metric ton.
  • The greatest possible error is half of 1 metric ton, which is 0.5 metric tons.
  • The measurement of 5 centimetres was made to the nearest whole centimetre.
  • The greatest possible error is half of 1 centimetre, which is 0.5 centimetres.
  • The measurement of 8 centimetres was made to the nearest whole centimetre.
  • The greatest possible error is half of 1 centimetre, which is 0.5 centimetres.

Let’s practice!🖊️